Thermostatic switch



Oct. 13, 1942. s CRUM 2,298,823

` THRMGE''ATIC SWITCH Filed oct. 15, 1959 lll/[11111114141111111/11//1//11/1/11lll/111111111 5 6 numtor Stephen @ummm .IFI gogh 3936E as /fLQ-vx MM i i attorney li Patented Oct. 13, 1942 THERMOSTATICSWITCH Stephen Crum, Minneapolis, Minn., assigner toMinneapolis-Honeywell Regulator Company,

Minneapolis, Minn., a corporation of Delaware Application October 13,1939, Serial No. 299,315

21 Claims.

This invention is directed generally to thermostatic switches, and moreparticularly to that type of switch which is adapted to respond to thevariations in temperature of the surface of a member.

One of ,the objects oi the present invention is to improve theconstruction of devices of this character so that they may be moreeasily made and assembled, and so that they may be more easilycalibrated and adjusted.

Another object is to mount the thermostat housing outside and on therear of the main switch casing and to provide it witha pair of mountingarms which are rotatable about said housing through 360 degrees. Thusthe device may be vertically mounted on a pipe or other surfaceregardless of whether it is horizontal, vertical, or any position inbetween.

Another object is to provide a simple and novel means of adjusting thecontrol setting of the device from outside the casing and to provide ascale on the adjusting arm which can be readily observed.

Still another object of the invention is to have a single resilientmember which holds a rotatable carriage for the thermostat and theadjusting arm therefor in operative relation with the casing, and alsosupplies the frictional force on the adjusting arm to maintain it in itsadjusted position. This resilient member relies upon openings in thesides of the casing for holding it in operative position.

These and other objects will readily become apparent as the followingspecication is read in the light of the accompanying drawing, in

which Figure 1 is a front elevation of the control device with the coveron,

Figure 2 is a side view partially in section, taken along the line 2-2of Figure 1,

Figure 3 is a section taken along the line 3-3 of Figure 2,

Figure 4 is a detail view of the mounting for one end of the resilientmember which holds the parts in assembled relation,

Figure 5 is a plan view of the adjusting arm with an adjustable stopattached, and

Figure 6 is a front elevation of the adjusting arm and stop shown inFigure 5.

Referring now to the drawing it will be seen that the casing I I whichis adapted to be mounted in a vertical position supports the variousparts which go to make up the control device of the present invention.Suitably connected erally circular in outline. This housing may beprovided with a series of extensions I3 (Figure 3) which pass throughslots in the casing II and are bent over as shown to securely connectthe housing I2 to the rear of the casing II. The casing II is providedwith a hole I4 in which is rotatably mounted the sleeve I5. Secured tothe sleeve I5 inside of the housing I2 is a supporting arm I6 whichcarries at its upper end I1 one end' of a coiled bimetallic thermostatI8. The arm I6 seats against a shoulder I9 on the sleeve I5 and issecured to the sleeve by peening over the end of the sleeve.

Seated against an opposite shoulder 2| on the sleeve I5 is a disc 22which has a circumferential depression 23 adapted` to bear against therear surface of the casing II. If desired a special bearing member maybe placed on the rear of the casing II to cooperate with circumferentialdepression 23 to provide a bearing surface and obtain a more uniformsliding friction as the disc 22 is rotated.

The sleeve I5 is provided with a reduced end 24 which forms a thirdshoulder against which a centering washer 26 is adapted to seat. Anadjusting arm 21 is provided with a hole which receives the washer 26 asthe adjusting arm is mounted over the sleeve I5. Mounted over thereduced portion 24 of the sleeve I5 and engaging the washer 26 and aportion of the adjusting arm 21 is a bearing washer 30. The aboveenumerated parts are held in assembled relation with respect to eachother and with respect to the casing II by means of a resilient member32 which is provided with a central hole 33 which receives the reducedportion 24 of the sleeve I5. The resilient member 32 is provided with areduced end 35 which extends through a hole 3I in the right-hand side ofthe casing II as seen in Figure 3 and a second reduced end 36 whichextends through a hole 31 in the other side oi the casing II. Engagementof these ends Within the holes 36 and 31 cause the resilient member tobow in the middle and force the disc 22 agains the rear of the casing II and also to maintain the washers 26 and 30 as well as the adjustingar'fn 21 in assembled relation with respect to the slee-ve I5 and casingII.

Referring to the detail view in Figure 4 it i be seen that the hole 31is provided with a w cned portion 36 adjacent the rear of the cas Il anda reduced part 39 which is just w enough to receive the reduced en.resilient member 32. The widene:

to the rear of the casing Il is a housing I2 gen- 55 provided so that inassembling the de. e n

36 including the shoulders 40 may be inserted through the widenedportion 38 as the resilient member 32 is moved to the left as seen inFigure 3 to permit the end 35 to be swung downwardly until itcan bemoved into the hole 36 provided for it in the casing II. After the end35 has been put in position to be inserted into the hole 36, theresilient member is moved to ward the right at which time the hole 33receives the reduced end 24 of the sleeve I5 and the end 36 of themember 32 is released to permit it to enter the reduced portion 39 ofthe hole 31. It will'be appreciated that as the holes 3| and 31 arelocated adjacent the rear of the'casing II that the resilient member 32is bent so as to exert a force on the sleeve I tending to move it towardthe right as seen in FigureV 2. This action forcesV the disc 22 againstthe casing II thereby producing a friction which resists rotationpi thedisc 22.

The ciuter`Y end of the bimetallic helix I8 is carried by the'ed I1 ofthe arm I6 and the inner end is connected to the actuating rod 42 whichextends through the opening in the sleeve I5 and into the casing II. Theinner end of the rod 42 carries a member 43 which is adjustablypositioned thereon by means of the screw 44. Member 43 supports theswitch clip 45 inA which is mounted the mercury switch 46. The wire 41is used to secure the switch 46 in the proper position in the switchclip 45.

Adjusting arm 21 is provided with arcuate slot 49 through which ispasseda screw 56 which enters a tapped hole 5I in an extension 52 on thebearing disc 22. By this arrangement the relative positions of thebearing disc 22 and the adjusting arm 21 may be varied in order tocalibrate the control device. The adjusting arm 21 is provided with ahorizontal extension 54 and avportion 55 which is spaced from therear ofthe casing II and which extends downwardly to a point just belowthe axisof the rod 42. The portion 55 of the arm 21 carries a head 56 which hasa kerf 51which is adapted to receive the blade of a screw-driver. Thishead 56 is on the axis of the actuating rod 42 about which the adjustingarm 21 is rotated. Therefore if the head 56 Is rotated byV means of ascrew-driver it will not be displaced other than in a rotary sense andthe adjusting arm 21 will be rotated about the axis 42.

. A cover 60 is adapted to b e placed about the casing II to completelyenclose the mercury switch, the adjusting arm 21 and related parts. Thecover 60 is provided with a plurality of indentations 6I which t intoholes 62 in thecasing II in order to frictionally maintain the cover :onthe casing lI I. The cover 60 is provided with a. hole 63 in its facewhich receives a portion of the head 56 so that a screw driver may beapplied thereto for rotating the adjusting arm 21 while the cover is inplace. Directly above the hole 63 is a second hole 65 through which aportion of the adjusting arm may be seen. This portion of the arm may beinscribed with a scale 66 for indicating the adjustment of the controldevice. The hole 65 may have an indicating pointer 61 forcooperationwith the scale and a window of transparent material may close this holeif desired.

A mounting device generally indicated at 'I0 i which is provided with apair of arms 1I and a central opening 12 having sloping sides 13 ismounted over the thermostat housing I2. Each of the arms is providedwith a hole 'I4 by means tached to the arms for mounting the controldevice on a pipe orother member to whose temperature the thermostat I8is adapted to re` spond, so that the rear of the housing I2 is held inheat conducting relationship with the surface of the pipe or member. Itwill be noted that the housing I2 extends slightly beyond the arms 1I sothat as the strap connected to the arm 1I is tightened the housing I2will be drawn into rmer engagement with the surface of the member onwhich it is being mounted. It will further be ,noted that the member I0may be rotated about the housing I 2 through 360 so that the device maybe mounted in a vertical position regardless of the angular position ofthe member 10 so long as this member is in a vertical plane. In otherwords, the device may be mounted with equal facility on a pipe whichextends vertically; horizontally or any position in between. A furtherfeature to be notedis that as the strap is drawn tighter the slopingsides 13 of the member 10 grip the sides and the housing I2 more firmlythereby resisting rotation of the casing II with respect to the member10. Therefore when the control device is once mountedl and the straptightened it will remain in a vertical position.

With the control device mounted as described above the heat from themember to which it is Ymounted will be conducted through the housing I2and to the bimetallic element I 8. This will cause the element to expandand the coiling and uncoiling of this element due to expansion andcontraction will cause a rotation of the actuating rod 42 and henceanrotation of the mercury switch 46 to make and break\ the circuittherethrough. It will be seen that the bimetallic element I8 is soproportioned with respect to the rod 42 and mercury switch 46 that itwill carry these elements entirely by its own resistance so that nor.-mally the actuating rod 42 is free of the sleeve I5 and does not restupon the sides of the hole 43 through this sleeve.

As set forth above in order to adjust the temperature at which theswitch 46 will make and break the circuit, the head 56 is rotated bymeans of a screw-driver causing thearm 21 to rotate about the actuatingrod 42' as a center.y As the arm 21 rotates it carries with it the disc22 and sleeve I5 which in turn rotates the outer end of the bimetalliccoil I8 thereby Varying the position of the mercury switch 46 and henceadjusting the temperature setting of the device. The relative rotationprovided between the adjusting arm 21 and the extension 52 of the disc22 `permits'the proper calibration of the thermostat I8 with respect tothe scale 66. It will be noted that the adjusting arm 21 is providedwith two angular extensions 16 and that the rotation `of the arm 21 islimited by the engagement of one or the other of these extensions 16with the resilient member 32.

In some cases it may be desirable to limit the extent to which thedevice may be adjusted in addition to the limit normally provided by theengagement of one of the extensions 16 with the resilient member 32. Inorder to provide for this an auxiliary stop member may be mountedconcentrically on the head 56 as shown at 8| in Figures 5 and 6. Thisstop member is provided with a rearwardly extending portion 82 and agenerally horizontally extending portion 83 which is provided with aslot 84. r'I'he screw 85 extends through a hole in the portion 54 of theadjusting arm 21 and through the slot 84 in the stop member 80. A nut 86is screwed on the end of the screw '85 and is adapted to be tightenedagainst the portion 83 of the stop B0 in order to lock the stop 80 andthe adjusting arm 21 in any predetermined position. It will be notedthat the horizontally extending portion 83 may extend out beyond theangular extension 16 on the adjusting arm 21 vso that as the adjustingarm'21 is rotated in a clockwise direction as viewed in Figures 3 and 6,the extension 83 on the stop member 80 will engage the resilient member32 thereby limiting the rotation of the arm 21.

' The stop member 80 is provided with a shoulder 81 which cooperateswith the scale 86 to indicate the temperature to which the adjustment ofthe arm 21 has been limited. In other words, if it is desired to limitthe temperature to which this device may be adjusted to 200 the member80 is set by means of the screw 85 and nut 86 until the shoulder 81points to the 200 mark on the scale 66. When this adjustment has beenmade the extension 83 will engage the resilient member 32 when thedevice has been set to 200 thereby preventing any further adjustments toa higher temperature.

vThe usual leveling indicator 90 is provided so that it can readily bedetermined when the casing II has been mounted in the proper verticalposition.

As various changes and modifications of this invention may occurto thosewho are skilled in the art, it is to be understood that I am to belimited only by the scope of the appended claims and not by the specificembodiment disclosed.

I claim as my invention:

1. In a device of the character described, an assembly comprising aswitch casing and a thermostat housing mounted on said casing outsidethereof, said housing having a surface adapted to be placed against abody to whose temperature the thermostatis to respond, a thermostat insaid housing, a switch in said casing actuated by said thermostat, andmeans for mounting said assembly so that said surface of the housing isheld against said body. said means being movable with respect to saidassembly so that the assembly may be properly levelled when it ismounted.

2. In a device of the character described. an assembly comprising aswitch casing and a thermostat housing mounted on said casing outsidethereof, said housing having a surface adapted to be placed against abody to whose temperature the thermostat is to respond, a thermostat insaid housing, a switch in said casing actuated by said thermostat, andmounting means rotatably carried by said housing for holding saidsurface against said body, said rotatable mounting means facilitatinglevelling of said assembly as it is being mounted.

3. A device of the character described comprising in combination, acasing having an aperture, a sleeve rotatably mounted in said aperture,a coiled birnetalilc thermostat outside of said casing and connectedatvone end to said sleeve, a rod extending through said sleeve andconnected to the other end of said thermostat for rotation thereby, aswitch within said casing actuated by said rod, a housing for saidthermostat attached to and projecting from saidgasing, and meanscooperating with said housing foi-supporting said ..device with onesurface of said housing against a body to whose temperature thethermostat responds, said means being rotatable with respect to saidhousing whereby said device may be levelled as it is mounted.

4. A device of the character described comprising in combination, acasing having an aperture, a sleeve rotatably mounted in said aperture,a coiled bimetallic thermostat outside of said casing and connected atone end to said sleeve, a rod extending through said sleeve andconnected to the other end of said thermostat for rotation thereby, aswitch within said casing actuated by said rod, a housing for saidtherniostat attached to and projecting from the back of said casing.means cooperating with said housing for supporting said device with theback surface of said housing against a body to whose temperature thethermostat responds, said means being rotatable with respect to saidhousing whereby said device may be levelled as it is mounted, an arm forrotating said sleeve and hence adjusting the temperature at which saidthermostat will actuate said switch, a scale on said arm, means forrotating said arm, a cover for sald casing having aperture means in thefront thereof through which a portion of the scale indicative of theadjustment of the thermostatt may be seen, and through access may be hadto the means for rotating said adjusting arm.

5. A 'device of the character described comprising in combination, aswitch casing, a sleeve extending through an aperture in said casing, acoiled bimetallic thermostat located outside of said casing, one end ofsaid thermostat being positionY by said sleeve, a switch inside of saidcasing, means controlled by the other end of said thermostat andextending through said sleeve to actuate said switch, an arm forrotating said sleeve and hence adjusting the temperature' at which saidthermostat will actuate said switch, a scale on said arm, a cover forsaid casing, said cover having indicating means including an aperture inthe front thereof by means of which that portion of the scale indicativeof the adjustment of the thermostat may be seen, and means for rotatingsaid arm, said last named means being in substantial alignment with saidsleeve, said cover having a second aperture in the front thereof inalignment with said rotating means for access thereto.

6. A device of the character described comprising in combination, aswitch casing, a sleeve extending through an aperture in the rear ofsaid casing, a coiled bimetallic thermostat located outside of saidcasing, one end of said thermostat being positioned by said sleeve, aswitch inside of said casing, means controlled by the other end of saidthermostat and extending through said sleeve to actuate said switch, anarm for rotating said sleeve and hence adjusting the temperature atwhich` said thermostat will actuate said switch, said arm having aportion extending substantially parallel to the rear of said casing,means on the last named portion of said arm in substantial alignmentwithsaid sleeve for rotating said arm and sleeve, a cover for said casing,and a scale on said parallel portion of said arm, said cover havingindicating means including an aperture by means of which that portion ofthe scale indicative of the adjustment of the thermostat is visible,said cover being provided with a second aperture by means of whichaccessmay be had to the means for rotating said adjusting arm.

7. A device of the character described comprising in combination, aswitch casing, a sleeve extending through an aperture in said casing, a

coiled bimetallio thermostat located outside of said casing, one end ofsaid thermostat being positioned Vby said sleeve, a switch inside ofsaid Casing, means controlled by the other end of said thermostat andextending through said sleeve to actuate said switch,A an arm forrotating said sleeve and hence adjusting the temperature at which saidthermostat will actuate said switch, indicia for` indicating theadjustment thereof, said casing being provided with means for limitingthe rotation of said arm, adjustable means for varying the extent towhich said limiting means will limit the rotation of said arm, and anindicator cooperable with said adjustable means and said indicia forindicating the limit setting.

8. A device of the character described comprising in combination, aswitch casing, a sleeve extending through an aperture in said casing, acoiled bimetaliic thermostat located outside of said casing, one end ofsaid thermostat being positioned by said sleeve, a switch inside of saidcasing, means controlled by the other end of said thermostat andextending through said sleeve to actuate said switch, an arm forrotating said sleeve and hence adjusting the temperature at thermostatand extending through* said sleeve, and switch means actuated by saidrod.

12. In a device of the character described, a switch casing, a sleeverotatably mounted in the rear of said casing, a bearing surface on saidcas- Y ing, a bearing member carried by said sleeve.

which said thermostat will actuate said switch,

indicia for indicating the adjustment thereof, said casing beingprovided with means for limiting the rotation of said arm, adjustablemeans for varyng the extent to which said limiting means will limit therotation of said arm, said last mentioned means being adjustably carriedby said adjusting arm, and an indicator cooperable with said adjustablemeans and said indicia for indicating the limit setting.

9. In 'a device ofthe character described, a casing, means rotatablymounted in the rear of said casing, said means having a bearing portion,said casing being provided with a. bearing surface cooperating with saidbearing portion, resilient means urging said rotatable means inengagement with said bearing surface, the sides of said casing havingholes with which the ends of said resilient means engage, thermostaticmeans connected at one end to said rotatable means, and' a control`device actuated by the other end of said thermostatic means.

l0. In a device of the character described, a switch casing, a sleeverotatably mounted in the rear of said casing, a bearing surface on saidcasing, a bearing member carried by said sleeve, an elongated resilientmember` seated over said sleeve and having reduced ends formingshoulders, said reduced ends extending through apertures in oppositesides of the casing, said shoulders abutting said sides, a thermostatmounted at one end on said sleeve, a rod connected to the other end ofsaid thermostat and extending through said sleeve, and switch meansactuated by said rod. Y

11. In a device of the character described. a switch casing, ausleeverotatably mounted in the rear of said casing, a bearing surface on saidcasing,a bearing member carried by said sleeve an elongated resilientmember seated over said sleeve and having reduced ends formingshoulders, said reduced ends extending through apertures in oppositesides of the casing, said shoul- `ders abutting said sides, one of saidapertures having a wider portion adapted to receive the shoulders at oneend of said resilient member as the other end is being mounted in'itsaperture, a thermostat mounted at one end on said sleeve, a rodconnected to the other end of said operating said control meanssupported by said an elongated resilient member seated over said sleeveand having reduced ends forming shoul-` ders, said reduced endsextending through apertures in oppOsite sides of the casing, saidshoulders abutting said sides, a thermostat mounted at one end on saidsleeve, a rod connected to the other end of said thermostat andextending through said sleeve, switch means actuated by said rod, andmeans for manually rotating said sleeve whereby the temperature at whichthe thermostat actuates said switch is'varied.

13.. In a device of the character described, a switch casing, a sleeverotatably mounted in the rear of said casing, a bearing surface on s'aidcasing, a bearing member carried by said sleeve, an elongated resilientmember seated over said sleeve and having reduced ends formingshoulders, said reduced ends extending through apertures in oppositesides of the casing, said shoulders abutting said sides, a thermostatmounted at one end on said sleeve, a rod connected to the other end ofsaid thermostat in a manner to be rotated thereby on temperaturechanges, said rod extending through said sleeve and within said casing,and a mercury switch mounted on the end of said rod within said casing,

14. In a device of the character described, a switch casing, a sleeverotatably mounted in the rear of said casing, a bearing surface on saidcasing. a bearing member carried by said sleeve, an elongated resilientmember seated over said sleeve and having reduced ends formingshoulders, said reduced ends extending through apertures in oppositesides of the casing, said shoulders abutting said sides, a thermostatmounted at one end on said sleeve, a rod connected to the other end ofsaid thermostat in a manner to be rotated thereby on temperaturechanges, said rod extending through said sleeve-and within said casing,a mercury switch mounted on the end of said rod within said casing, andmeans for rotating the sleeve whereby the temperature at which thethermostat actuates the mercury switch is varied.

15. In a device of the character described, control means, a casingtherefor, a thermostat for casing so as to project exteriorly thereof, ahousing for said thermostat attached to said casing and having a surfaceadapted to be placed against a body to whose temperature thethermostatresponds, said housing being of substantially circular cross-sectionwith an enlarged portion adjacasing so as to project exteriorly thereof,a housing for said thermostat attached to said casing and having asurface adapted to be placedagainst a body to whose temperature thethermostat re- .means of which said surface may be pressed against saidbody, said pressing action holding said collar in engagement with saidtapered portion, thereby resisting relative rotation therebetween.

17. A device of the character described comprising in combination, aswitch casing, a sleeve extending through an aperture in said casing, acoiled bimetallic thermostat located outside of said casing, one end ofsaid thermostat being positioned by said sleeve, a switch inside of saidcasing, means controlled by the other end of said thermostat andextending through said sleeve to actuate said switch, an arm forrotating said sleeve and hence adjusting the temperature at which saidthermostat will actuate said switch, a

stationary member in said casing for limiting the rotation of said arm,and a member adjustab y mounted on said arm for engaging said stationarymember. said adjustably mounted member serving to vary the limitingposition to which said arm may be moved in one direction.

18. In a device of the character described, a casing, thermostatic meansmounted at one side of said casing, a switch, means operativelyconnecting said switch to said thermostatic means, means for supportingsaid switch and said connecting means, and an elongated resilient memberfor holding said supporting means against said side of said casing, saidelongated member having a central portion adapted to engage saidsupporting means and reduced end portions forming shoulders, saidreduced ends extending through apertures in opposite sides of saidcasing laterally disposed from said one side, said shoulders abuttingsaid opposite sides, one of said apertures having a wider portionadapted to receive the shoulder at one end of said member as the otherend is being mounted in its aperture.

19. In a device of the character described, a switch casing, a sleeverotatabiy mounted inthe rear of said casing, a bearing surface on saidcasing, a bearing member carried by said sleeve, an elongated resilientmember seated over said sleeve and having reduced ends formingshoulders, said reduced ends extending through apertures in oppositesides of the casing, said shoulders abutting said sides, a thermostatmounted at one end on said sleeve, a rod connected to thev other end ofsaid thermostat and extending through said sleeve, switch means actuatedby said rod, an arm for rotating said sleeve whereby the temperature atwhich said thermostat actuates said switch is varied, and a projectionon said arm for engaging said resilient member to limit the rotation ofsaid arm.

20. In a device of the character described, a switch casing, a sleeverotatably mounted in the rear of said casing, a bearing surface on saidcasing, a bearing member' carried by said sleeve, an elongated resilientmember seated over said sleeve and having reduced ends forming shculders, said reduced ends extending through aper* tures in opposite sidesof the casing, said shoul ders abutting said sides, a thermostat mountedat one end on said sleeve, a rod connected to the other end of saidthermostat and extending through said sleeve, switch means actuated bysaid rod, an arm for rotating said sleeve whereby the temperature atwhich said thermostat actuates said switch is varied, and a memberadjustably mounted on said arm -ior engaging said resilient member tolimit the rotation of said arm.

2l. A device of the character described comprising in combination., aswitch casing, a sleeve extending "b ough aperture in said casing, acoiled bime thermostat located outside of said casing, one end of saidthermostat being positioned bv said sleeve, a switch inside of saidcasing, mear controlled by the other end of said thermostat extendingthrough said sleeve to actuatesaid switch, an arm for rotating saidsleeve i hence adjusting the temperature at which d thermostat willactuate said switch, stop means on said casing for limiting the rotationoi said arm, adjustable means on said -arm for said stop to vary thelimiting position to which said arm may be moved in one direction, and ascale on said arm, said casing having an aperture therein by means ofwhich that portion of the scale indicative of the actuating temperatureof the thermostat may be seen, said adjustable means having a portioncooperating with said scale to indicate the limit of said actuatingtemperature as determined by said adjustable means.

' STEPHEN CRUM.

